Semiconductor nuclear radiation detectors are used in a large variety of fields, including nuclear physics, X-ray and gamma ray astronomy, and nuclear medicine. Such detectors may have good imaging capabilities, energy resolution, and the ability to be fabricated compactly. Compound semiconductors with wide band gap and high atomic number are used for X-ray and gamma ray detectors. The quality of crystals used for detectors can be improved, and precipitates can be avoided, by applying the modified Bridgman technique or by post-growth thermal annealing. In these procedures, a small cadmium excess is provided in an ampoule. During the modified Bridgman crystal growth process, one ampoule end is kept at a lower temperature that determines a nearly atmospheric constant vapor pressure in the system. The growth process involves continuous material transfer between the three phases. The constant vapor pressure keeps a constant liquid composition, and provides balanced amounts of cadmium and tellurium within the crystal. FIGS. 1A and 1B illustrate the horizontal and vertical versions of this technique without the presence of a Cd reservoir at the cold end. In both cases the crystal grows from the melt by moving along a region with a temperature gradient that extends from above to below the melting point. The growth may proceed by mechanically moving the ampoule or by moving the heating furnace. The growth procedure starts by melting the separate tellurium from cadmium and zinc loads. Often the compounding occurs under a hydrogen atmosphere in order to remove oxygen from the system. The materials are then brought into contact and heated until they react and produce CdZnTe source material used for crystal growth. The material can also be produced by compounding CdTe and ZnTe separately and mixing them into the desired proportions to produce CdZnTe ingots by the Bridgman growth technique.